How does phenotypic plasticity happen?

  • Instantaneous / instinctual responses
    • behavior or physiology


  • Gene expression responses
    • process by which the information encoded in a gene is turned into a function
    • increased or decreased production of RNA/proteins


  • Epigenetic responses
    • structural changes to DNA that change how your body reads a DNA sequence
    • mechanisms where DNA is not accessible for transcription
    • DNA nucleotide sequence does not change
    • possibly inherited

Different types of genetic changes

Changes to DNA sequence underlie adaptation

Changes to gene expression underlie plasticity

Changes to gene expression underlie plasticity (epigenetic)

Phenotypic plasticity: Instantaneous / instinctual response

Noise pollution impacts communication, mating, predator-prey, etc.

Noise pollution is prevalent in marine systems too

Phenotypic plasticity: Instantaneous / instinctual response

Natural light cycles are drive function for many organisms

Phenotypic plasticity: Gene expression responses

Larval bees have identical DNA sequences. Changes in gene expression, likely from an enzyme in royal jelly, alter the development of the larva.

Phenotypic plasticity: Gene expression responses

Changes in gene expression from drought exposure can alter the # of stomata produced, where the are located and how fast the open/close

Phenotypic plasticity: Epigenetic response


Vinclozolin is a fungicide used by farmers to stop rot, mold and blight


Vinclozolin linked to great granddaughter’s stress via DNA methylation (inherited)



DDT, the first modern pesticide, has been banned in USA since 1972


Pregnant female mice fed DDT and their female offspring had a lower tolerance for cold temperature and were more obese

Changes to gene expression underlie plasticity

Traditionally, it was thought that changes to the sequence of DNA were heritable while changes to the expression patterns of DNA were not


That made it easy to define adaptation as “heritable genetic change” and plasticity as “non-genetic”

Epigenetics blurs those lines

The adjust response

Adjust: non-genetic shifts in organismal traits in different environments (phenotypic plasticity)


The adjust response happens at the level of the individual and happens within a single generation (MOSTLY)


The adapt response (Chapter 7) happens at the level of the population and happens across generations


  • Can plasticity and adaption be connected?
    • can plasticity buy time: YES
    • can plasticity promote adaptive genetic change:?
      • phenotype produced with enhanced survival…
      • loss of plasticity after environmental change…
      • selection of more or less plasticity would be adaptation

Meet the Data: Shifts with global warming


What shifts (in space and time) do we see most commonly for organisms with global warming?



  • Geographic shifts toward the poles


  • Geographic shifts up in elevation


  • Geographic shifts deeper in oceans


  • Seasonal shifts earlier in the year
    • earlier springs AND longer falls

Phenotypic plasticity in development: Examples from insects

As ecotherms, temperature matters a lot for insect survival, development, dispersal, etc.


Insect life histories are tied to environmental factors

Phenotypic plasticity in development: Examples from insects


  • Major effect of global warming on insects is to speed up developmental rates
    • can lead to faster maturity



In the UK >70% of butterfly species studies have earlier “first flight”


First flight is predicted to occur 2-10 days earlier for every 1°C

Phenotypic plasticity in development: Examples from insects


  • Major effect of global warming on insects is to speed up developmental rates
    • can lead to more generations per year



Increase of temperatures by 2°C is predicted to allow some aphid species to produce an additional 4–5 generations per year.


Aphids are among the most destructive insect pests on cultivated plants

Phenotypic plasticity in development


Temperature-induced advancement in development is common and relates to a broader pattern…


Phenological changes: changes in periodic biological phenomena (like flowering, breeding, migration)

Phenotypic plasticity in development


2003 meta-analyses found an advancement of an average of 2.3 days per decade

Remarkably consistent across groups (and that was 20 years ago!!!)

Phenotypic plasticity in development


  • With global warming we expect many temperature dependent processes to occur earlier in the year
    • Even a few days matters


Phenological mismatch: When interacting species are no longer temporally or spatially aligned (Chapter 9)


  • Biodiversity loss is linked with Phenological mismatches
    • no organism is infinitely plastic
    • mismatches impact many species in food webs

Friday Discussion: Can Humans Adjust to Global Change?


  • How do humans adjust (short-term changes) to environmental change


  • What evidence exists? Past, present and/or future
    • can we acclimate to …..
    • what traits are plastic (or not)?
    • human behavioral shifts…
    • are specific genes involved (for bio people)?
    • do any phenological mismatches exists with other species?


  • Be prepared to discuss what you found as well as your opinion on if it is possible


  • Submit an article/finding on Brightspace for participation